Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Nf6/4. Ng5

Two Knights Defence
a b c d e f g h 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1 a b c d e f g h
Position in Forsyth-Edwards Notation(FEN) r1bqkb1r/pppp1ppp/2n2n2/4p1N1/2B1P3/8/PPPP1PPP/RNBQK2R
Moves: 1. e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5
ECO code: C57-C59
Parent: Italian Game

Two Knights Defence

4. Ng5

This move is interesting. While some in the past considered it ridiculous, others point out that White wins a pawn in the process.

The White Knight now threatens a fork with Nxf7, yet to do so it's broken a rule of opening development in that the same piece moves twice. Black's only sensible way to defend f7 is to block the bishop access with 4...d5, however the pawn on d5 itself is not fully defensible by Black.

Black has two sensible replies.

• 4...d5 The best way for Black to defend is to play, blocking the bishop from the weak f7 square.
• 4...Bc5. Ignoring the threat, a risky option is the Traxler Attack. Black can try a bishop sacrifice on f2 if White plays Nxf7. Instead, White will often prefer Bxf7+.

Additionally, black may choose to move the knight on f6. This opens up an attack on the white g5 knight. There are two sensible methods of achieving this:

• 4...Nxe4.
• 4...Nd5.

Theory table

For explanation of theory tables see theory table and for notation see algebraic notation

1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5

		4	5	6	7	8	9	10
Two Knights Defence	1	Ng5 Bc5!?	Bxf7+ Ke7	Bd5 Rf8	O-O d6	c3 Bg4	Qb3 Bb6	Bxc6 bxc6	+/=
	2	... d5	exd5 Nxd5!?	d4 Bb4+	c3 Be7	Nxf7 Kxf7	Qf3+ Ke6	Qe4 Rf8	+/=
	3	... ...	... ...	Nxf7!? Kxf7	Qf3+ Ke6	Nc3 Ncb4	a3 Nxc2+	Kd1 Nxa1	∞
	4	... ...	... Na5	d3 h6	Nf3 e4	Qe2 Nxc4	dxc4 Bc5	Nfd2 O-O	=
	5	... ...	... ...	Bb5+ c6	dxc6 bxc6	Be2 h6	Nf3 e4	Ne5 Bc5	∞
	6	... ...	... ...	... ...	... ...	... ...	Nh3 Bd6	d3 O-O	∞
	7	... ...	... ...	... ...	... ...	Qf3 Be7	Bxc6+ Nxc6	Qxc6+ Bd7	∞
	8	... ...	... b5	Bf1 h6	Nxf7 Kxf7	dxc6 Qd5	Qf3 Qc5	b4 Qxb4	∞
	9	... ...	... Nd4	c3 b5	Bf1 Nxd5	Ne4 Qh4	Ng3 Bg4	f3 e4
	10	... Nxe4!?	Bxf7+ Ke7	d4 d5	Nc3				+=
	11	... Nd5	d3						+=

Statistics

Estimated next move popularity
d5 80%, Bc5 19%, Others less than 1%

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References

• Batsford Chess Openings 2 (1989, 1994). Garry Kasparov, Raymond Keene. ISBN 0-8050-3409-9.

• Nunn's Chess Openings. 1999. John Nunn (Editor), Graham Burgess, John Emms, Joe Gallagher. ISBN 1-8574-4221-0.